aurora 4t80e transmission problem please help

I bought a 1996 oldsmobile aurora was told it had a bad trans. Dropped the pan to find a bad shift solenoind... borken. Bought the replacement kit with 2 shift solenoids and filter and retainer. Bought new spacer plate and gasket set. Put it all back together and still no reverse. It shifts great forward now but no reverse. I can hear it engaging.....i think i missed a step when istalling it. Does anyone know what i did wrong? am i supposed to do somthing with a shim when taking it out? i seem to remember reading that somewhere but i dont have alldata onymore. Can anyone help. I really dont want to pull the trans out and put a new one it. I think it must be somehing simple i need to do on the reveres but i dont know what. Please help.